Cleaning out old system users - how?

Hi All

I’ve decided to move from my own Google Home integration to Nabu Casa. I’ve found out that it works very nicely, and I’ve decided to stay with Home Assistant, as I’m beginning to learn more about it (thanks to all you guys!!!, the docs are still really bad :-D).
I’ve tried out the nabu casa previously, and I now have some left-over users that I want to get rid of before reapplying for nabu casa.
users
But as they are system users, I can’t remove them via the GUI, so how do I get rid of them?

I also see a .cloud folder under config, which I guess I should get rid of as well?